Ch. x.i 



TEETH OF EXTINCT MAMMALIA. 



133 



while the latter have been more persistent than the univalves, whether 

 gasteropoda or cephalopoda. In like manner the specific identity of 

 the characters of the foraminifera, which are among the lowest types 

 of the invertebrata, has outlasted that of the mollusca in an equally 

 decided manner. 



Teeth of post-pliocene mammalia. — To those who have never studied 



Fig. 112 a. • 



Elephas primigenius (or Mammoth); molar of upper jaw, right side; one third of nat. size. 

 Post-pliocene. a. Grinding surface. b. Side view. 



comparative anatomy, it may seem scarcely credible that a single 

 bone taken from any part of the skeleton may enable a skilful oste- 

 ologist to distinguish, in many cases, the genus, and sometimes the 

 species, of quadruped to which it belonged. Although few geologists 

 can aspire to such knowledge, which must be the result of long prac- 

 tice and study, they will nevertheless derive great advantage from 

 learning, what is comparatively an easy task, to distinguish the prin- 

 cipal divisions of the mammalia by the forms and characters of their 

 ceeth. 



The annexed figures represent the teeth of some of the more com" 

 mon species and genera found in alluvial and cavern deposits. 



Fig. 113. 



EUphas ontiquus, Falconer. Penultimate molar, one-third of nat. size. 

 Post-pliocene and pliocene. 



